1. Field of the Invention
The present invention relates to developing device and developing method that are used in image forming apparatus such as printers, copying machines, etc.
2. Description of the Related Art
For developing devices of image forming apparatus such as printers, copying machines, etc. to obtain images according to an electro-photographic system, there is so far available an image forming apparatus provided with a narrow portion comprising developer containers and developing rollers arranged closely at a point near the opening of a developing container so as to prevent a developer in a developing container from leaking to the outside during the development or when moving a developing device and this narrow portion is blocked up by a napping of a developer formed on the surface of the developing roller. Particularly, in the case of developing devices available in recent years, that are installed to a revolver and arranged positions of them are changed by rotating them en block to supply different color developers, there is a merit to effectively prevent leakage of developers from developer containers when turning a revolver by providing the above-mentioned narrow portion.
Or, a revolver is provided with a sealing member to block up a clearance between a developing container and a developing roller at the opening of the developer container in order to prevent leakage of developer caused when turning a revolver as disclosed in Japanese Patent Publication No. 2000-75592.
However, the above-mentioned conventional developing devices so far available have not a function to recover toner scattered from carriers in a developer container when toner is separated from carrier and scattered as a result of rotation of developing roller during the developing operation. In a conventional developing device with the above-mentioned narrow portion provided, as the opening of the developer container is not blocked up by a sealing member, scattering toner is once directed to the inside of a developer container from the opening on the air flow caused from the rotation of the developing roller but bounced by the napping portion blocking the narrow portion and scatters again to the outside of the developing container. On the other hand, in a conventional developing device with a sealing member provided at the opening, scattering toner scatters in the periphery without solely taking in a developing container and contaminates periphery equipment or adversely affecting images.
Accordingly, it is desired so far to obtain a developing device that is capable of certainly recovering scattering toner generated when turning a developing roller in a developer container, preventing toner to scatter in the periphery of developing device, obtaining clear images without contaminating peripheral equipment and images by attaching scattering toner to them and reducing frequency of maintenance.
An object of the present invention is to provide a developing device and a developing method without generating contamination of the periphery by scattering toner by recovering scattering toner generated during the developing operation in developing containers and preventing scattering of toner in the periphery.
According to an embodiment of the present invention, in the image forming devices comprising developer containers for housing developers, rotatable image carriers for supplying developers to electrostatic latent images formed on an image carrier and a narrow portion provided with an inner wall of the developer container and the developer carrier arranged closely at a point near the opening of the developer container, a developer recovery sheet that floats from the developer carrier when turning the carrier is provided, of which one end is attached to the end of the opening of the developer container and the free end is extended in the direction of the narrow portion in the developer container.
Further, according to the embodiment of the present invention, in a developing method using the developing devices provided with the narrow portion comprising the inner wall of the developer container and a rotatable developer carrier closely arranged at a point near the opening of the developer container, the developer recover sheet of which one end is attached to the end of the opening of the developer container and the free end is extended in the direction of the narrow portion in the developer container floats from the developer carrier.